Stamp-shoe.



O. L. LAWTON.

STAMP SHOE.

APPLICATION I'ILED JULY 1,1911.

Patented Dec. 26, 1911.

CHARLES I1. LAWTON, OF HANCOCK, MICHIGAN.

STAMP-SHOE.

Specification of Letters Patent.

Patented Dec. 26, 1911.

Application filed July 1, 1911. Serial No. 636,470.

To all whom it may concern."

Be it known that I, CHARLEs L. LAWTON, a citizen of the United States, and a resident of Hancock, in the county of I-Ioughton and State of Michigan, have invented a new and useful Stamp-Shoe, of which the following is a specification.

This invention relates to metal shoes of stamp-mills, and its object is to provide a shoe which shall have a long working-life, and which shall retain the most effective working face for the greatest possible length of time.

In the accompanying drawings, Figure 1 is a transverse section of a mold for the shoe. Fig. 2 is a plan of a chill. Fig. 3 is a cross section of a shoe with section lines to indicate the relative hardness of the metal. Figs. 4, 5 and 6 are plans of different forms of shoes.

The lower edges. of ordinary stamp shoes quickly wear away, resulting in a convex face. This wearing continues until the lower portion of the shoes becomes quite round and therefore inefficient. Instead of crushing the ore, the shoe simply rams it or ushes it away, resulting in a great decrease of the output of the mill. When the shoe is so formed that the outer edge of the wearing face is harder than the middle portion, the sharp particles of quartz or other rock will wear away the middle of the face substantially as fast as the outer edge. The action of the stamp is more effective when the bottom face of the shoe is slightly concave. Shoes of cast iron, formed by pouring the metal into a mold having a chilling member, have been found most effective, and to have the longest life. They virtually consist of a central core and an outer shell, the shell being much harder than the core.

The shoes may be of any desired form. Figs. 4, 5 and 6 show shoes 1, 2 and 3, that are of different cross sections. Any desired means may be employed to secure the shoes to the stamps, ribs 4 provided with boltholes 5 being shown in Figs. 5 and 6, while in Fig. 4 the rib 6 has a curved side 7 and a straight side 8, inclined toward each other so as to furnish attaching means for the stamp head. The chill 9 sired thickness, depending upon the depth and degree of hardness desired.

The flask 10 may be of the usual construction, and the sand 11 may be either 4 77 or C dry-77 To insure slow cooling of the middle or core of the shoe a pad 12 of asbestos, properly prepared sand, or other good non-conductor of heat, may be placed in the bottom of the mold. A portion 13 of the mold may be of dry sand to properly form the rib 6.

The output of ore per stamp when equipped with a shoe having a hard outer edge and softer middle portion, and the life of the shoe, are both much greater than those of a shoe of uniform hardness to or even greater than the hardness of the outer edge of the shoe of this invention, owing to the fact that the shoe of uniform hardness becomes rounded while the shoe of this invention remains slightly concave or flat.

The shoe of the present invention may be used until substantially worn away, while the usual shoe of uniform hardness throughout often becomes practically useless when less than one fourth of its volume has been lost.

The depressions 14 in the bottom faces of the shoes may be of any desired dimensions.

Having now explained my improved stamp-shoe, what I claim as my invention and desire to secure by Letters Patent is A shoe for stamp-mills consisting of an integral member of cast met-a1 having a relatively softer exposed working axial portion and a harder outer portion, said metal gradually increasing in hardness from the axial ortion to the outer surface of said shoe.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

CHAS. L. LAWTON.

Witnesses:

RICHARD T. MfiHLHAUSER, W. M. BELL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

will be of any de-- equal 

